well i only have ubuntu on my laptop and iam not that expert and i tried yestreday to install lxde but it didnt install because of no internet connection i think, iam downloading 11.04 livecd now and all my data (100GB) are in the home folder as i dont have other partitions can u tell me how to remove gnome3 and get back to unity or actually re-installing 11.04 without loosing data?
Thank you very much

You are given the opportunity to use safe mode with internet access. If you are experiencing problem with the wireless, then the most easy solution is to use wire to install lxde. You can do the rest of the things wirelessly.

NOTE: This is assuming that you used the default, guided partitioning method.

Boot up the live CD and enter the installer.
When you get to the "Allocate Drive Space" Section of the installer, chose "Something Else" (what a descriptive name.) This will take you into the manual partition editor.
Find your Ubuntu partition on the list, right-click on it and say "Change."
In the resulting window, change the "Use as:" section to "Ext4 jouraling file system"
Then set the "Mount point" to "/"
Click OK, and AFTER you get back to the main partitioning window make sure that the "Format?" section is UNchecked. If you used a file system other than Ext4 in the original installation, it will force a format because it has to change the file system.
If the partition is not marked for formating, go ahead and finish the installation making sure to use the exact same name, user-name and password as you did in the original installation. If you don't, it can mess things up.
That's all! You will have to reinstall any programs you had before, but all your files and program settings will still be there.

ANOTHER NOTE: If you are using this method to install a DIFFERENT version of Ubuntu than the one you're starting with, it may be a good idea to delete the hidden files containing program settings in your home folder to prevent problems with different program versions.

By the way, I'm having the same problem with the /ICEauthority file. I haven't tried all the posted fixes yet, but I'll write back if something works.

But if that doesn't work try to, as said, install LXDE and then boot into it. After that you should be able to boot Gnome Shell. I had to add the command "gnome-shell --replace" to autostart because it didn't start at login (I did it through LXDE because I couldn't do much in Gnome at that point). If everything works then, you can uninstall lxde with the command: